It probably isn't a good idea to write on your new fancy flat screen, but if you're still using an old glass-screen CRT, usobe0 calls it the perfect dry-erase surface:

Some people scoff that I still have a big CRT television, but it's one of the best resources I have to get things done. When I need to remember something or do something, I pull out a dry erase marker and write on the screen, because it's glass it works just like a board. The TV is centrally located so I see it all the time and it gives me a pretty good guilt trip when I try to procrastinate.

Sure, it's probably not a reason to throw out your giant living room LCD or plasma for an old CRT, but you could easily replace your small home office TV with a CRT and this would still work well. You can also apply it to anything you use to procrastinate, as long as it's made out of glass—whether it be writing on your Mac's trackpad to dissuade you from game-playing or your reading glasses to dissuade you from kicking back with a Sudoku when you should be working. Got any of your own guilt-tripping tactics to keep you from slacking off? Share them with us in the comments.